The present invention relates to a signal processing circuit that subjects an input signal to signal processing, thereby generating an output signal, and, more particularly, to a technique of producing an output signal that achieves a balance between a sense of full-bodied sound and distortion.
In a related amplifier, when it is detected that a level of an output signal reaches to a source voltage, an input signal is attenuated, thereby preventing occurrence of clipping, which would otherwise be caused by an input signal having an excessive high level. Patent Document 1 discloses a technique for detecting occurrence of clipping without fail and attenuating an input signal, because it is difficult to make an accurate determination as to whether or not clipping has actually occurred by detection of a level of an output signal.
Patent Document 2 discloses a technique for enhancing a sense of full-bodied sound by allowing a certain degree of clipping in an output signal.
[Patent Document 1] JP-A-10-163769
[Patent Document 2] JP-A-2008-301035
A principal objective of the technique described in Patent Document 1 is to prevent occurrence of clipping. To this end, if clipping occurs or if there is a chance of occurrence of clipping, an input signal will be immediately attenuated. However, such control entails performance of excessive quick attenuation operation, which in turn raises a problem of deficiency in a senses of full-bodied sound.
Meanwhile, the technique described in Patent Document 2 allows a certain degree of clipping and rises a problem of an increase in distortion.